Ansari Fard got on the end of Pejman Nouri's cross to break the deadlock in the 63rd minute at Qatar Sports Club Stadium as Iran claimed their second consecutive victory in Group D following the opening 2-1 triumph over neighbours Iraq.
The opening exchanges saw plenty of commitment from both sides but chances were hard to come by and it took until the 16th minute for Jong Tae-se to warm the hands of Iran keeper Mahdi Rahmati, with An Young-hak driving the rebound well off target from outside the box.
Ansari Farid then saw a goal ruled out for handball as the game settled into a midfield battle before Jong once again was presented with a sight of goal five minutes from the break after a ball was lifted over the Iran defence, but the striker's angled shot was held by Rahmati.
That prompted a flurry of action as Kim Kuk-jin tried his luck from some way out but his effort flew well wide before Nouri sliced a volley from the edge of the box horribly off target after the midfielder had made a late run.
The second period began in much the same vein as the opening half.
Mohammad Reza Khalatbari's weak shot was easily dealt with at the near post by Ri Myong-guk in the 58th minute but five minutes later, Iran took the lead.
Nouri latched onto a throw in down the left flank and whipped in a cross that Ansari Fard managed to steer past the diving Ri and into the far corner to send the lively Iranian support into raptures.
Cha Jong-hyok's low shot from 25 yards forced Rahmati into a low save as he scrambled across his goal to palm the ball away to safety.
The North Koreans did begin to show more attacking urgency after falling behind and nearly snatched a dramatic equaliser in stoppage time.
Hong Yong-jo managed to escape the attentions of the Iran defence to collect a low cross, before swivelling and firing a powerful shot from 12 yards, only to see his effort graze the top of the Iran crossbar, much to the forward's anguish as Iran closed out the victory.